Finnish Patent Specification 57996 discloses an oil collecting vessel comprising two oil booms arranged in V-shape. The booms are provided with power shafts for rotating rotors attached thereto, whereby the rotors displace oil from beside the booms in the sideward direction to the path of travel of the vessel, wherefrom a conveyor band positioned in front of the vessel passes the oil into the vessel. This vessel cannot be used for collecting oil from the surface of water containing ice blocks, because the rotors are not capable of displacing the ice blocks but are damaged. The rotors do not increase the efficiency of the oil collecting process to any greater extent, and part of the oil escapes under the booms so that the conveyor band will not catch it.
U.S. Pat. No. 4,196,087 discloses an oil collecting device, wherein the flow of oil-containing surface water into the collecting gates of the device is made more efficient by positioning screwlike booms radially around the device, whereby the device can be displaced by operating these booms selectively. Such a radial structure, however, is not suitable for use in large independently operated vessels.